KR101044203B1 - Electromagnetic bandgap structure and Printed circuit board having the same - Google Patents

Abstract

The present invention relates to an electromagnetic bandgap structure and a printed circuit board including the same, wherein the electromagnetic bandgap structure includes a dielectric layer, a plurality of conductive plates formed on the dielectric layer, and an electrical connection between two adjacent conductive plates among the plurality of conductive plates. A first via formed through the dielectric layer, the first via connected to one of the two neighboring conductive plates, the first via connected to one of the two neighboring conductive plates, and the first connected to the other one of the two neighboring conductive plates Stitching vias including a second via, one end connected to the other end of the first via, and the other end connected to the other end of the second via, and a first dummy formed in the conductive plate in the thickness direction of the dielectric layer. Even if analog and digital circuits, including vias, are implemented on the same printed circuit board, mixed signal problems can be solved.

Mixed Signal, Electromagnetic Wave, Band Gap, Stitching Via, Dummy Via, Ground Layer, Power Layer

Description

Electromagnetic bandgap structure and printed circuit board having the same

The present invention relates to an electromagnetic bandgap structure and a printed circuit board including the same.

Recently introduced electronic and communication devices are becoming smaller, thinner and lighter. Such electronic devices and communication devices include a combination of various electronic circuits (analog circuits or digital circuits) for implementing the functions / operations of the device, and these electronic circuits are generally mounted on a printed circuit board to provide the corresponding functions. Will be performed. In this case, the electronic circuits mounted on the printed circuit board are mostly different from each other.

Therefore, in a printed circuit board in which various electronic circuits are mounted in combination, an electromagnetic wave (EM wave) caused by the operating frequency of one electronic circuit and its harmonics is generally transmitted to and interfered with another electronic circuit. Therefore, a noise problem (a problem of mixed signals) occurred.

Conventionally, in order to solve such a mixed signal problem, a circuit board having a built-in bypass capacitor is used, but a method of blocking high frequency noise has not been a proper solution.

Recently, a coplanar electromagnetic bandgap (EBG) structure has been proposed as a solution to the mixed signal problem between digital and analog circuits. The coplanar EBG is a general form in which EBG cells having a characteristic of not passing a specific frequency are repeatedly formed in the entire ground layer.

  The coplanar EBG structure is formed by repeatedly forming a wide area and a narrow area of the conductor in the entire area of the ground layer or the power layer. In order to obtain a high impedance value, adjacent cells are connected by forming a long conductive line pattern. In this case, a relatively large area is required to form a long conductive line pattern, resulting in design limitations.

In particular, the design difficulty is further increased when a large number of active and passive devices are required in a narrow wiring area such as a package board or a circuit board in which a digital circuit and an analog circuit are implemented on the same board as the main board of a mobile phone. Big.

The present invention was devised to solve the above problems, and proposes an electromagnetic bandgap structure having a low bandgap frequency and reducing noise of a specific frequency and a printed circuit board including the same.

In addition, the present invention ensures a high impedance even in a small area, it is possible to secure the design in the manufacture of a printed circuit board dense active and passive elements.

The electromagnetic bandgap structure according to the present invention is formed for electrical conduction between a dielectric layer, a plurality of conductive plates formed on the dielectric layer, and two neighboring conductive plates of the plurality of conductive plates, penetrating the dielectric layer and having one end thereof A first via connected to one of two neighboring conductive plates, a second via penetrating the dielectric layer and one end connected to the other of the two adjacent conductive plates, one end connected to the other end of the first via, A stitching via configured to include a connection pattern having the other end connected to the other end of the second via, and a first dummy via formed in the conductive plate in the thickness direction of the dielectric layer.

In addition, the first dummy via is characterized in that any one of a conical or cylindrical.

In addition, the first dummy via is formed by filling a conductive paste inside the via.

In addition, the plurality of conductive plates are formed on the same plane.

The apparatus may further include a conductive layer positioned with the plurality of conductive plates and the dielectric layer interposed therebetween.

The method may further include a second dummy via formed in the conductive layer in the thickness direction of the dielectric layer.

The conductive layer may include a clearance hole, and the connection pattern may be accommodated in the clearance hole.

The second dummy via may be formed at a position corresponding to the first dummy via formed on the conductive plate.

In addition, another electromagnetic bandgap structure according to the present invention is formed for electrical conduction between a dielectric layer, a plurality of conductive plates formed on the dielectric layer, and two adjacent conductive plates of the plurality of conductive plates, but penetrate the dielectric layer. A first via, one end of which is connected to one of the two neighboring conducting plates, a second via that passes through the dielectric layer and one end of which is connected to the other of the two neighboring conducting plates, the other end of the first via Stitching vias connected to the ends and having a second end connected to the other end of the second vias, a conductive layer positioned between the plurality of conductive plates and the dielectric layer, and a thickness of the dielectric layer in the conductive layer. And a second dummy via formed.

In addition, the second dummy via is characterized in that any one of a conical or cylindrical.

In addition, the second dummy via is formed by filling a conductive paste inside the via.

The conductive layer may include a clearance hole, and the connection pattern may be accommodated in the clearance hole.

In addition, the printed circuit board according to the present invention includes a printed circuit board including two electronic circuits having different operating frequencies, wherein the printed circuit board is disposed between the two electronic circuits, a dielectric layer and a plurality of conductive plates formed on the dielectric layer. A first via formed through the dielectric layer, the first via penetrating the dielectric layer and having one end connected to any one of the two neighboring conductive plates; A second via, one end of which is connected to the other of the two adjacent conductive plates, a stitching via configured to include a connection pattern, one end of which is connected to the other end of the first via, and the other end of which is connected to the other end of the second via, and And an electromagnetic bandgap structure including a first dummy via formed in the conductive plate in the thickness direction of the dielectric layer.

The electromagnetic bandgap structure may further include a conductive layer positioned between the plurality of conductive plates and the dielectric layer.

The method may further include a second dummy via formed in the conductive layer in the thickness direction of the dielectric layer.

The conductive layer may include a clearance hole, and the connection pattern may be accommodated in the clearance hole.

In addition, the conductive layer is any one of a ground layer or a power layer, the conductive plate is characterized in that it is electrically connected to the other.

In addition, the conductive layer is a ground layer, characterized in that the conductive plate is electrically connected to the signal layer.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The electromagnetic bandgap structure according to the present invention has a small size but has a low bandgap frequency to reduce noise of a specific frequency.

In addition, the printed circuit board according to the present invention ensures a high impedance even in a small area in the manufacture of a printed circuit board with a dense active and passive elements, it is possible to secure the design. And, even if multiple RF circuits or digital circuits are implemented on the same substrate, the mixed signal problem can be solved.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components as possible, even if displayed on different drawings have the same number as possible. In addition, in describing the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a three-dimensional perspective view showing a part of the electromagnetic bandgap structure 100 according to a preferred embodiment of the present invention, Figure 2 is taken along line A-A 'of the electromagnetic bandgap structure 100 shown in FIG. 3 is a modified example of the electromagnetic bandgap structure 100 shown in FIG. 2. Hereinafter, the electromagnetic bandgap structure 100 according to the present embodiment will be described with reference to this.

As shown in FIGS. 1, 2 and 3, the electromagnetic bandgap structure 100 according to the present embodiment electrically connects a plurality of conductive plates 110 (110a, 110b) and neighboring conductive plates 110a, 110b. It includes a stitching via 130 to connect to the dummy via 140 formed in the conductive plate 110. In addition, the conductive plate 110 may include a conductive layer 150 positioned between the dielectric layer 120.

The basic structure of the electromagnetic bandgap structure 100 has a two-layered planar structure having one conductive layer 150 as one layer and two conductive plates 110 as two layers. In this case, the conductive layer 150 and the conductive plate 110 are separated by the dielectric layer 120.

Here, the electromagnetic bandgap structure 100 illustrated in FIGS. 1, 2, and 3 simplifies only essential components for convenience, but the plurality of conductive plates 110 and the conductive layer 150 are multilayer printed circuits. There may be two layers inside of the substrate. In addition, it is apparent that at least one other metal layer may exist between the conductive plate 110 and the conductive layer 150.

At this time, the conductive plate 110 is preferably located on the same plane, and separated by a predetermined interval. The conductive plate 110 transmits an electrical signal as a metal plate (eg, copper plate).

In addition, the conductive layer 150 is also made of a metal layer.

The stitching via 130 electrically connects two neighboring conductive plates 110a and 110b. However, two conductive plates 110 are not connected on the same plane, but are connected via different layers. A detailed review is as follows.

The stitching via 130 includes a first via 131, a second via 132, and a connection pattern 133 connecting the vias. One end of the first via 131 is connected to the conductive plate 110a, and the other end of the first via 131 is connected to one end of the connection pattern 133. One end of the second via 132 is connected to the second conductive plate 110b, and the other end thereof is connected to the other end of the connection pattern 133. Accordingly, both ends of the connection pattern 133 may be connected to the first via 11 and the second via 132, and may include via lands for the connection.

In this case, the first via 131 and the second via 132 may have a form in which a plating layer is formed only on an inner wall to electrically connect the conductive plate 110, or a plating layer is formed on the entire interior thereof. Or it may be a form filled with a conductive paste therein.

Accordingly, the neighboring first conductive plate 110a and the second conductive plate 110b are connected through the first via 131, the connection pattern 133, and the second via 132.

Meanwhile, the first conductive plate 110a may be adjacent to other conductive plates other than the second conductive plate 110b. Accordingly, the first conductive plate 110a may be electrically connected to another conductive plate other than the second conductive plate through another stitching via. If the first conductive plate 110a has a rectangular shape, it will be connected to four stitching vias for electrical connection with four adjacent conductive plates. However, the conductive plate 110 is not limited to the quadrangular shape, but may have various shapes such as a triangular shape, and may be formed of a plurality of groups having different sizes.

Since the conductive plates 110 are connected through the stitching vias 130, there is no need to form a pattern for connecting the conductive plates on the two-layer plane. Therefore, the gap between the conductive plates 110 formed on the two-layer plane becomes narrow, and the area of the conductive plate 110 is widened. Therefore, the capacitance appearing in the gap between the conductive plates can be increased.

In addition, the dummy via 140 is formed in the conductive plate 110 in the thickness direction of the dielectric layer 120 (to the first dummy via 140 to distinguish it from the dummy via formed in the conductive layer 150 described later). Reference). Unlike the first via 131 or the second via 132 forming the stitching via 130, the first dummy via 140 has one end connected to the conductive plate 110, but the other end thereof is disconnected from another metal layer. It is a shape. Therefore, the dielectric layer 120 may be formed to partially penetrate in the thickness direction. The length of the first dummy via 140 may be adjusted within the thickness of the dielectric layer 120.

Since the first dummy via 140 is formed on the conductive plate 110, the gap between the conductive layer 150 constituting the lower electrode layer of the capacitor and the conductive plate 110 constituting the upper electrode layer of the capacitor is narrowed therebetween. The capacitance is increased.

The shape of the first dummy via 140 may be formed in a cylindrical shape as shown in FIGS. 1 and 2. The cylindrical first dummy via 140 is easy to manufacture. In addition, as shown in Figure 3, it may be formed in a conical shape. In the conical first dummy via 140 ′, charges are concentrated at the vertex of the cone, thereby concentrating the capacitance between the first dummy via 140 ′ and the conductive layer 150 at the vertex of the first dummy via 140 ′. To be. On the other hand, the shape of the first dummy via 140 is not limited to a cylinder and a cone.

The first dummy via 140 may have a form in which a plating layer is formed only on an inner wall thereof, but preferably, the conductive paste is filled in the via. The conductive paste is generally a metal paste, and enables the transfer of charge between the conductive plate 110 and the first dummy via 140.

Meanwhile, in FIG. 1, five first dummy vias 140 are formed in one conductive plate 110, but the number thereof is not limited.

In addition, a clearance hole 155 may be formed in the conductive layer 150 to accommodate the connection pattern 133 therein. The clearance hole 155 may have a shape that can accommodate the via land in addition to the connection pattern 133. The clearance hole 155 electrically separates the stitching via 130 and the conductive layer 150.

Meanwhile, the conductive plate 110 is connected to another metal layer that is distinguished from the conductive layer 150. When the conductive layer 150 is a power layer, the other metal layer becomes a ground layer, and the conductive plate 110 is connected to the ground layer, and in the opposite case, the conductive plate 110 is connected to the power layer.

4 and 5 are cross-sectional views of an electromagnetic bandgap structure according to another preferred embodiment of the present invention. Hereinafter, the electromagnetic bandgap structure according to the present embodiment will be described with reference to this.

As shown in FIG. 4, the electromagnetic bandgap structure 200 according to the present embodiment includes a dielectric layer 220, a plurality of conductive plates 210 formed on the dielectric layer 220, a stitching via 230, and a plurality of conductive plates. A conductive layer 250 disposed between the 210 and the dielectric layer 220, and a dummy via 245 formed in the conductive layer 250 in the thickness direction of the dielectric layer 220. .

Here, the shape and function of the conductive plate 210, the dielectric layer 220, the stitching via 230, and the conductive layer 250 are the same as those described above with reference to FIGS. 1 to 3, and thus a detailed description thereof will be omitted.

In this case, the conductive layer 250 includes a second dummy via 245 formed in the thickness direction of the dielectric layer 220. The second dummy via 245 is similar in structure and function to the first dummy via 140 described above.

However, the second dummy via 245 is formed in the conductive layer 250 instead of the conductive plate 210, and increases capacitance with the conductive plate 210.

As shown in FIG. 5, the electromagnetic bandgap structure 300 according to the present embodiment has the thickness of the dielectric layer 320 in the conductive layer 350 in the electromagnetic bandgap structure 100 shown in FIGS. 1 to 3. It characterized in that it further comprises a dummy via 345 formed in the direction.

 The second dummy via 345 is also formed in the thickness direction of the dielectric layer 320. The shape and structure of the second dummy via 345 is similar to the first dummy via 340 described above, and thus a detailed description thereof will be omitted.

The second dummy via 345 affects an increase in capacitance between the conductive plate 310 and the conductive layer 350. The second dummy via 345 reduces the distance between the conductive layer 350 and the conductive plate 310, and charges are concentrated at the ends of the second dummy via 345 and increase capacitance with the conductive plate 310. Let's do it.

In addition, the second dummy via 345 may be formed at a position corresponding to the first dummy via 340 described with reference to FIGS. 1 to 3. Be careful not to connect the end of the first dummy via 340 and the end of the second dummy via 345. At this time, charges are concentrated at the ends of the first dummy via 340 and the second dummy via 345, so that the capacitance increases between both ends.

The printed circuit board including the above-described electromagnetic bandgap structure will be described. The printed circuit board may include a plurality of electronic circuits, where the electronic circuits may have different operating frequencies.

Such a printed circuit board includes a power supply layer and a ground layer, and includes a signal layer and a ground layer. The conductive layer may function as either a power supply layer or a ground layer. The plurality of conductive plates may be connected between neighboring conductive plates through stitching vias to form one closed circuit, thereby functioning as the other of the power supply layer or the ground layer.

In addition, when a printed circuit board is applied as a SiP (System in Package) substrate, the conductive layer may function as a ground layer, and the plurality of conductive plates may serve as a signal layer. The signal transmitted along the signal layer generates noise due to a high operating frequency. In this case, the above-described electromagnetic bandgap structure is applied to reduce noise having a specific frequency.

Two electronic circuits of different operating frequencies are arranged spaced apart with an electromagnetic bandgap structure in between. Two electronic circuits are examples of digital circuits and analog circuits.

An electromagnetic bandgap structure may be disposed between the electronic circuits to shield or reduce noise of a specific frequency band among electromagnetic waves transmitted from a digital circuit to an analog circuit. This reduces the problem of mixed signals occurring in analog circuits.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, such modifications or variations will have to belong to the claims of the present invention.

1 is a three-dimensional perspective view of an electromagnetic bandgap structure according to a preferred embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA ′ of the electromagnetic bandgap structure shown in FIG. 1.

3 illustrates a modification of the electromagnetic bandgap structure shown in FIG. 2.

4 is a cross-sectional view of an electromagnetic bandgap structure according to another preferred embodiment of the present invention.

5 is a cross-sectional view of an electromagnetic bandgap structure according to another preferred embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100, 200, 300; Electromagnetic bandgap structures 110, 110a, 110b; Conduction plate

120, 220, 320; Insulating layers 130, 230, 330; Stitching Via

131, 231, 331; First via 132, 232, 332; Second via

133, 233, 333; Connection patterns 140, 140 ', 240; First dummy via

245, 345; Second dummy vias 150, 250, 350; Conductive layer

155; Clearance hall

Claims (18)

Dielectric layer; A plurality of conductive plates formed on the dielectric layer; A first via which is formed for electrical conduction between two adjacent conductive plates of the plurality of conductive plates, the first via penetrating the dielectric layer and one end connected to any one of the two adjacent conductive plates, A second via connected to the other one of the two adjacent conductive plates, and a stitching via configured to include a connection pattern, one end of which is connected to the other end of the first via and the other end of which is connected to the other end of the second via; And A first dummy via formed in the conductive plate in a thickness direction of the dielectric layer; Electromagnetic bandgap structure comprising a. The method according to claim 1, The first dummy via is any one of a conical or cylindrical, characterized in that the electromagnetic bandgap structure. The method according to claim 1, The first dummy via is an electromagnetic bandgap structure, characterized in that the conductive paste is filled inside the via. The method according to claim 1, The plurality of conductive plates are formed on the same plane electromagnetic bandgap structure. The method according to claim 1, Electromagnetic bandgap structure further comprises a conductive layer positioned between the plurality of conductive plates and a dielectric layer. The method according to claim 5, The conductive layer has a clearance hole, And the connection pattern is received in the clearance hole. The method according to claim 5, The conductive layer further comprises a second dummy via formed in the thickness direction of the dielectric layer. The method of claim 7, And the second dummy via is formed at a position corresponding to the first dummy via formed in the conductive plate. Dielectric layer; A plurality of conductive plates formed on the dielectric layer; A first via which is formed for electrical conduction between two adjacent conductive plates of the plurality of conductive plates, the first via penetrating the dielectric layer and one end connected to any one of the two adjacent conductive plates, A second via connected to the other one of the two adjacent conductive plates, and a stitching via configured to include a connection pattern, one end of which is connected to the other end of the first via and the other end of which is connected to the other end of the second via; A conductive layer positioned between the plurality of conductive plates and a dielectric layer; And A second dummy via formed in the conductive layer in a thickness direction of the dielectric layer; Electromagnetic bandgap structure comprising a. The method according to claim 9, The second dummy via is an electromagnetic bandgap structure, characterized in that any one of a conical or cylindrical. The method according to claim 9, The second dummy via is an electromagnetic bandgap structure, characterized in that the conductive paste is filled inside the via. The method according to claim 9, The conductive layer has a clearance hole, And the connection pattern is received in the clearance hole. In a printed circuit board comprising two electronic circuits of different operating frequencies, Disposed between the two electronic circuits and formed for electrical conduction between a dielectric layer, a plurality of conductive plates formed on the dielectric layer, and two neighboring conductive plates of the plurality of conductive plates, penetrating the dielectric layer and having one end A first via connected to one of the two neighboring conductive plates, a second via penetrating the dielectric layer and one end connected to the other one of the two neighboring conductive plates, one end connected to the other end of the first via And an electromagnetic bandgap structure including a stitching via having a second end including a connection pattern connected to the other end of the second via, and a first dummy via formed in the conductive plate in a thickness direction of the dielectric layer. 14. The method of claim 13, The electromagnetic bandgap structure further comprises a conductive layer positioned between the plurality of conductive plates and the dielectric layer. The method according to claim 14, The conductive layer further comprises a second dummy via formed in the thickness direction of the dielectric layer. The method according to claim 14, And the conductive layer has a clearance hole, and the connection pattern is accommodated in the clearance hole. The method according to claim 14, The conductive layer is any one of a ground layer or a power layer, and the plurality of conductive plates are electrically connected to the other. The method according to claim 14, And the conductive layer is a ground layer, and the plurality of conductive plates is electrically connected to a signal layer.

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